In a new study, middle-aged women with the most frequent RLS episodes were 41% more likely to have high blood pressure than women without the disorder, and the prevalence of high blood pressure increased with RLS symptom frequency.

The findings strongly suggest that restless legs syndrome increases the risk for high blood pressure, but more research is needed to confirm the association, says researcher Salma Batool-Anwar, MD, MPH, of Brigham and Women’s Hospital and Harvard Medical School.

“We cannot say from this study that restless legs syndrome causes blood pressure to rise, but we did see a significant relationship between the severity of (RLS) symptoms and prevalence of hypertension,” she tells WebMD.

RLS and the Heart, Studies Mixed

More than 5 million people in the United States have moderate to severe restless legs syndrome, and an even greater number have a milder form of the disorder, according to the National Institutes of Health.

Sufferers report throbbing, pulling, and other unpleasant sensations in the legs when sitting or lying down. This often leads to the overwhelming urge to move the legs to get the symptoms to go away, hence the name “restless legs syndrome.”

Women are twice as likely as men to have RLS, and although symptoms can occur at any age, the disorder is most common in middle-aged people and the elderly.

The condition is often associated with poor quality sleep, which can lead to daytime fatigue, depression, and other health problems associated with lack of sleep.

Although some studies have found an increased risk for heart attack and stroke in patients with RLS, others have not shown the association.

Four out of five RLS sufferers also experience a more common nighttime movement disorder known as periodic limb movement of sleep (PLMS), which has been linked to elevations in heart rate and blood pressure.

1 in 3 With Severe RLS Had High BP

In an effort to better understand the impact of RLS on blood pressure, Batool-Anwar and colleagues analyzed data from the Nurses Health Study II, one of the largest and longest women’s health studies ever conducted.

The analysis included more than 65,500 female nurses whose average age was 50. The women were asked if they had experienced RLS, and, if so, to describe the frequency of their symptoms. They were also asked about their blood pressure status.

After taking into account the impact of lifestyle factors that raise the risk for high blood pressure -- such as obesity, advanced age, and smoking -- having restless legs syndrome was associated with a 6% to 41% increase in the risk for hypertension.

About one in four (26%) women who had five to 14 episodes of RLS each month had high blood pressure, compared to 1 in 3 (33%) who had more than 15 episodes and one in five (21%) who did not have RLS symptoms.

The study was published today online and will appear in the November issue of the American Heart Association journal Hypertension.

Sleep Deprivation May Be Key

If future research confirms the association, Batool-Anwar says treating RLS could have a beneficial effect on blood pressure and heart disease risk.

In some cases RLS appears to be caused by low levels of iron and studies suggest that treatment with iron supplements can be beneficial.

Optimal treatment of other conditions that are common in RLS patients, such as kidney failure and diabetes, may also improve symptoms.

But in most cases, there is no obvious cause for the movement disorder. Several medications are available to treat the symptoms of RLS.

Blood pressure specialist Domenic Sica, MD, says there is a growing body of research linking conditions that affect sleep quality like RLS with high blood pressure and heart disease.

He tells WebMD that the evidence linking poor quality sleep with heart and blood vessel disease risk is compelling.

In an editorial published with the study, Sica and colleague David Leszczyszyn, MD, write that the impact of sleep deprivation on risk factors for heart attack and stroke is only now being recognized.

“In the foreseeable future, the hypertension specialist and, for that matter, any clinician actively treating hypertension will need to have more than a just passing knowledge of sleep patterns and sleep-related diseases to most effectively treat hypertension and accompanying cardiovascular [heart and blood vessel] diseases,” they write.